I mean, with an interop-unlocked phone you might be able to replace the system font files. If you can find the right registry key and it's somewhere you can write, that might work too. I'm not aware of any other solution, though, certainly not for mere dev-unlock.
Frankly, if this is something you want, you should be researching it yourself. There aren't a lot of us developing WP8.x hacks, and we've all got day jobs and lives and all that. What's more, we're usually looking more for new ways to gain privileges, rather than things to do with the privileges we have. There's nothing wrong with starting out looking at how to apply the existing hacks more profitably; in fact, that's exactly how I started back in the WP7.0 days. Find things and post them, people will appreciate your efforts and the community will benefit, while other people work to ensure that more devices can be jailbroken.